Hello gurpreet
If you want to broad the spectrum of laser signals you can do the following things
1) use hnlf highly non linear fiber to broad spectrum over a freq. Band.using spm and xpm effects
2) you can use SOA as a non linear medium to broad the spectrum and distribute signal over different dreq. Signals
3) use EAM with the carving high freq. To upconvert or downconvert your signal
I think these suggedtion help you.if you need help to implement these systems,i can help you